Here's a quick vignette of where I think the e-mail etiquette/code of conduct was violated:
December 20: My boss e-mails me, cc's someone he wants me to contact, and says "E-mail or call John Doe* to get in touch."
Now, here comes the part where I screwed up somewhat royally -- I saw the e-mail, took note of it, *meant* to get on it soon, and then got sidetracked with holiday and family stuff. After Christmas, I wound up doing several straight days of work for a military course I'm doing, and then BAM -- in my inbox on the 29th is a not-so-happy note from my boss, with an e-mail string below where John Doe is whining about how it's been over a week, and he hasn't heard back from me, and it's really urgent and important that we get moving, etc.
Fair enough. That's an honest-to-goodness mistake. Time to apologize, move on, and get working. Besides, after he and I talked about it, the boss-man was totally fine with it.
But the more I thought it about, I'm coming away with a pretty rotten first impression of Mr. Doe. If the shoe were on the other foot, I'd like to think this is how I would've handled it -- if the matter were really so urgent, and the need to get moving so great, I would've gone ahead and e-mailed the person directly rather than firing a salvo right over his head, towards his boss. Just assume the best and say, "Hmmm...this Page fellow must've gotten sidetracked with the holidays and probably just forgot to send the note. I'll give him a quick *ping* just to remind him that he's supposed to coordinate this with me."
Instead, he sends a whiny e-mail right over my head, back to my boss, detailing the super-critical urgency of the situation and wondering why I haven't written or called him.
To me, that's not only passive-aggressive, but it goes against the general rule that first gets articulated by kids on a playground who shun the "tattler" -- if a dispute or misunderstanding can be solved at the lowest possible level (i.e. direct, person-to-person) it's always preferable to do it that way before you go running for a teacher or lunch aide.
* Name changed to protect the guilty